Die castable centrifugal fan

ABSTRACT

Disclosed herein is a fan assembly comprising a first fan member including a plurality of angularly space vane portions extending perpendicularly of the axis of intended fan rotation and perpendicularly to a plane perpendicular to the axis of intended fan rotation and having axially outer edges, a second fan member including a second plurality of vane portions corresponding in number and angular spacing to the vane portions of the first member, each of the second member vane portions having an axially inner edge and an axially outer part extending arcuately in a plane extending parallel to the intended axis of fan rotation and perpendicularly to a plane extending radially from and containing the intended axis of fan rotation, and separable interfitting means on the first and second fan members for aligning the outer edges of the vane portions of the first fan member with the inner edges of the vane portions of the second fan member and for rotatably driving one of the first and second fan members in response to rotation of the other of the first and second fan members.

United States Patent [191 Hackbarth et a1.

[ DIE CASTABLE CENTRIFUGAL FAN [75] Inventors: Eugene R. Hackbarth, Kenosha,

Wis.; Harry M. Ward, 111, Waukegan, Ill. [73] Assignee: Outboard Marine Corporation,

Waukegan, Ill.

[22] Filed: Oct. 3, 1973 [21] Appl. No.: 403,177

Related US. Application Data [62] Division of Ser. No. 320,073, Jan. 2, 1973, Pat. No.

[52] US. Cl. 29/156.8 CF [51] Int. Cl 821k 3/00 [58] Field of Search. 29/1568 CF; 415/143, 213 R; 416/183, 186

[56] References Cited UNITED STATES PATENTS 1,427,391 8/1922 Johns 416/183 1,959,703 5/1934 Birmann 4161183 2,138,814 12/1938 Bressler.... 416/183 2,398,203 4/1946 Browne 415/143 2,399,852 5/1946 Campbell et a1..... 415/143 2,482,462 9/1949 Browne 416/186 2,704,516 3/1955 Mock et a1 415/213 2,991,004 7/1961 Denbo et a1. 29/1568 CF 3,065,954 11/1962 Whitaker 416/183 3,285,187 11/1966 Anderson 29/156.8 CF

Canada 416/183 July 8, 1975 [57] ABSTRACT Disclosed herein is a fan assembly comprising a first fan member including a plurality of angularly space vane portions extending perpendicularly of the axis of intended fan rotation and perpendicularly to a plane perpendicular to the axis of intended fan rotation and having axially outer edges, a second fan member including a second plurality of vane portions corresponding in number and angular spacing to the vane portions of the first member, each of the second member vane portions having an axially inner edge and an axially outer part extending arcuately in a plane extending parallel to the intended axis of fan rotation and perpendicularly to a plane extending radially from and containing the intended axis of fan rotation, and separable interfitting means on the first and second fan members for aligning the outer edges of the vane portions of the first fan member with the inner edges of the vane portions of the second fan member and for rotatably driving one of the first and second fan members in response to rotation of the other of the first and second fan members.

5 Claims, 11 Drawing Figures 1 DIE CASTABLE CENTRIFUGAL FAN This is a division of application Ser. No. 320,073 filed Jan. 2, I973, now US. Pat. No. 3,782,85I.

BACKGROUND OF THE INVENTION The invention relates generally to internal combustion engines and more particularly to fan structures for air cooling internal combustion engines. Centrifugal type cooling fans have been provided in the past for delivering cooling air through a shroud and past the engine block of an internal combustion engine. Such fans have sometimes included vanes with swirl portions which provide for increased fan efficiency. However, due to the vane shape which affords the swirl construction, such fans were expensive to manufacture and were not capable of being die cast.

SUMMARY OF THE INVENTION The invention provides a method of die casting a cen trifugal fan having a plurality of vanes including a swirl configuration. In addition, the invention provides a fan assembly comprising a first fan member receivable on a rotary member and including a plurality of angularly spaced vane portions extending radially outwardly of the axis of rotation and perpendicular to a plane perpendicular to the axis of rotation and having axially outer edges. together with a second fan member received on the rotary member outwardly of the first fan member and including a second plurality of vane portions corresponding in number and angular spacing to the vane portions of the first fan member. Each of the second member vane portions has an axially inner edge and an outer part extending arcuately in a plane extending parallel to the rotary axis and perpendicular to a plane extending radially from and containing the rotary axis. In addition, separable interfitting means are provided on the first and second fan members for aligning the outer edges of the vane portions of the first fan member and the inner edges of the vane portions of the second fan member and for rotatably driving one of the first and second fan members in response to rotation of the other of the first and second fan members.

In further accordance with the invention, the interfitting means comprises a circumferential flange extending radially outwardly from the radially outer ends of the vane portions of the second fan member, which flange has a surface with a plurality of radially extending recesses therein, said recesses receiving the radially and axially outer parts of the first member vane portions.

In accordance with the invention, the method involves die casting the first fan member with a parting line located along a flange surface from which the vane portions extend. The method also involves die casting the second fan member with a parting line extending along the axially outer radially extending margins of the outer or swirling part of the vane portions. After die casting. the fan members are assembled in coaxial alignment and with the vane portions of the first and second members in alignment. Each of the fan members includes appropriate draft extending from the appropriate parting line.

One of the principal objects of the invention is the provision of a method of manufacturing a centrifugal fan which includes vanes having swirling portions and which is formed from die cast members.

Another of the principal objects of the invention is the formation of a centrifugal fan with swirling vanes, which fan can be die cast in two cooperating members each having appropriate drafts from an applicable parting line.

Another of the principal objects of the invention is the provision of an internal combustion engine including a fan assembly comprising inner and outer fan members, together with interfitting means for separably assembling the fan members on a crankshaft or other shaft in aligned relation and for rotatably driving the assembly from such shaft.

Another of the principal objects of the invention is the provision of a centrifugal fan including first and second die cast members. each of the members having separable interfitting parts affording proper alignment of the fan members.

Other objects and advantages of the invention will become known by reference to the following specifications, claims and drawings.

DRAWINGS FIG. I is a fragmentary view, partially in section. of an internal combustion engine including a fan assembly embodying various of the features of the invention.

FIG. 2 is an axially outer view of the inner fan member incorporated in the fan assembly shown in FIG. 1.

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2.

FIG. 4 is an enlarged view of the outer portion of the outer part of one of the vane portions of the fan member shown in FIG. 2.

FIG. 5 is a sectional view taken along line S5 of FIG. 4.

FIG. 6 is a sectional view taken along line 6-6 of FIG. 2.

FIG. 7 is an axially outer view of the outer fan member included in the fan assembly shown in FIG. 1.

FIG. 8 is a sectional view taken along line 8-8 of FIG. 7.

FIG. 9 is a sectional view taken along line 9--9 of FIG. 7.

FIG. 10 is an axially inner view of the outer fan member incorporated in the fan assembly shown in FIG. 1.

FIG. 11 is a sectional view taken along line 11-11 of FIG. 10.

Before explaining the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts set forth in the following general description or illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

GENERAL DESCRIPTION OF THE INVENTION Fragmentarily shown in the drawings is an internal combustion engine 11 including a crankcase or engine block which journals a crankshaft 15 having a portion 17 extending exteriorly of the engine block 13. Received on the extending crankshaft portion 17 is a fan assembly or unit 21 which cooperates with an engine shroud 23 to deliver cooling air around the engine block 13 and which,-in accordance with the invention, provides a centrifugal fan having a plurality of vanes 25 each with a swirl portion or configuration 27 affording increased fan efficiency. In order to permit die casting of the fan assembly 21 with swirl vane portions 27 (See FIG. 9) in accordance with the invention, the fan assembly includes two separable fan members 31 and 33, each capable of being die cast. More specifically, the fan assembly 21 includes the first or axially inner fan member 31 located adjacent to the engine block 13 and a second or axially outer fan member 33 located adjacent to and outwardly with respect to the engine block 13 of the inner fan member 31, together with interfit ting means on the fan members 31 and 33 for aligning the fan members 31 and 33.

Still more particularly, the first fan member 31 (See FIGS. 2 and 3) comprises a central hub 35 which is bored at 37 for receipt of the crankshaft portion 17 and which is counterbored at 39 to receive a part of the second fan member 33. The first or inner fan member 3| also includes a base or flange 41 which extends radially outwardly of the hub 35, and a plurality of angularly spaced vane portions 43 whichpreferably extend from the hub 35 and flange 41 and are approximately perpendicularly to a plane perpendicular to the crankshaft axis. The vane portions 43 each include a radially extending axially outer edge 45 located remotely from the engine block 13. Each outer edge includes a slightly tapering radially outermost part 47.

In addition, as shown best in FIG. 2, when seen in a plane perpendicular to the crankshaft axis, the vane portions 43 extend, at their radially outer ends, arcuately in the direction 49 of intended rotation to adjacent the periphery of the flange 41.

Die casting of the inner or first fan member can be accomplished by using a parting line 51 for the die casting operation extending generally along the axially outer surface 53 of the flange 41 from which the vane portions 43 extend. The first or inner fan member 31 also includes appropriate draft to provide for separation from the parting surface of the die members (not shown). Other parting line arrangements could be employed.

The second or outer fan member 33 also includes (as seen best in FIGS. 7, 8 and a central hub 61 which, when assembled with the inner fan member 31, projects into the counterbore 39. In addition, the central hub is apertured at 63 to permit passage therethrough of the crankshaft portion 17 and is counterbored at 65 as will hereinafter be referred to. Also included in the second or outer fan member 33 are a second plurality of vane portions 67 which extend radially outwardly from the central hub 61 and which correspond in angular spacing and number to the vane portions 43 of the first fan member 31. Each of the vane portions 67 includes an axially inner radially extending edge 69 located adjacent to the inner fan member 31. In order to provide the swirl configuration 27, each of the outer fan member vane portions 67 also includes an outer part 71 which extends arcuately in a plane extending parallel to the crankshaft axis and perpendicularly to a plane extending radially from and containing the crankshaft axis. Each of the outer parts 71 of the vane portions 67 of the outer fan member 33 has an axially outer margin 72;As shown in the drawings and particularly in FIG. 10, the vane portions 67 can be somewhat arcuately curved whenviewed in a plane perpendicular to the crankshaft axis to confonn to any curvature provided in the radially outer parts of the vane portions 43 of the inner fan member 31.

Extending from the radially outer ends of the vane portions is a generally cylindrical portion 73 which interconnects the vane portion outer ends and which, in cooperation with the central hub 61, defines an air inlet 74 for the fan assembly 21. The cylindrical portion 73 also supports a circumferential flange 75 which projects radially outwardly from adjacent the axially inner edges 69 of the vane portions 67. As can be seen best in FIGS. 8 and 10, the flange 75 includes a surface 77 which is located adjacent to the inner fan member 31 and which is slightly inclined toward the inner fan member so as to define, in the assembled fan 21 and in cooperation with the flange 41 of the inner fan member 31, a circumferentially extending outlet 79. Extending axially outwardly from the axially outer surface 81 of the flange 75 is a cylindrical portion 83 which interfits with a cylindrical groove 85 in the shroud 23 so as to provide a labyrinthe air seal.

Die casting of the outer or second fan member 33 can be accomplished by using a parting line 87 for the die casting operation extending generally along the outer margin 72 of the vane portions 67 and along the outer surface 81 of the flange 75. The second or outer fan member 33 also includes appropriate draft to provide separation from the parting line 87 of the die member (not shown). Other parting line arrangements can be employed.

In accordance with the invention, means are provided on the inner and outer fan members 31 and 33 for aligning the fan members 31 and 33. Such means also affords rotational driving of one of the fan members by the other. Various arrangements can be em ployed to align the fan members 31 and 33. For instance, means could be provided between the interfitting hubs 35 and 61 of the inner and outer fan members 31 and 33. In the illustrated construction, separable interfitting means are provided by utilizing the axially and radially outer parts 47 of the inner fan member vane portions 43 and by providing slots or recesses 91 in the undersurface 77 of the flange 75 of the outer fan member 33 for receipt of such outer parts 47 of the vane portions 43 of the inner fan member 31. As shown in the drawings in the illustrated construction, such slots 91 are provided by spaced arcuate projections 93 on the undersurface 77 of the flange 75 of the outer fan member 33. The location of such slots or recesses 91 insures alignment of the axial outer edges 45 of the vane portions 43 of the inner fan member 31 with the axially inner edges 69 of the vane portions 67 of the outer fan member 33 and simultaneously provides coaxial alignment between the inner and outer fan members 31 and 33.

In addition, receipt of the outer parts 47 of the vane portions 43 of the inner fan member 31 into the slots or recesses 91 in the outer fan member 33 permits rotational driving of either one of the fan members by the other fan member.

Means are provided for retainingthe fan members 31 and 33 in assembled, interfitted relation to each other and for retaining the fan assembly on the crankshaft. While various arrangements could be employed, in the illustrated construction such means comprises (See FIG. 1) formation of a shoulder 95 on the crankshaft 15 limiting axially inward movement of the inner fan member 31, together with formation of threads 97 on the outermost part of the crankshaft portion 17 and employment of a nut 99 threadedly received on the crankshaft portion 17, located in the counterbore 65 of the outer fan hub 61, and operable to retain the outer fan member 33 in interfitted relation with the inner fan member 31 and to retain the assembled fan members 31 and 33 on the crankshaft 15. lf desired, a washer can be employed between the nut 99 and the base of the counterbore 65 in the hub 61 of the outer fan member 33.

Means are also provided for rotatably driving the interfitted fan assembly 21 from the crankshaft 15. Various constructions could be employed. For instance, both fan members 31 and 33 could be keyed to the crankshaft 15. Alternatively, a driving member could be connected between the crankshaft 15 and one of the fan members 31 and 33, relying on the interfitting condition of the fan members 31 and 33 to provide common fan member rotation. In the illustrated construction, such a driving member comprises a key extending between the crankshaft l5 and the inner fan member 31.

While the invention has been described in connection with mounting on the crankshaft of an internal combustion engine 11, it should be noted that the fan assembly 21 is adapted for mounting on any shaft. In addition, the fan assembly 21 can be employed with any type of internal combustion engine.

In assembly, the inner fan member 31 is telescopically received on the exterior crankshaft portion 17 with the key 101 in driving connection between the crankshaft l5 and inner fan member 31. The outer fan member 33 is then slipped over the crankshaft 15 and arranged relative to the inner fan member 31 so as to interfit the cooperating interfitting means on the inner and outer fan members, whereby to axially align the fan members 31 and 33 and to align the vane portions 43 and 67 of the inner and outer fan members 31 and 33. Thereafter, the nut 97 is threaded on the outer end part of the crankshaft 15 to retain the inner and outer fan members 31 and 33 in assembled relation and to retain the assembled fan 21 on the crankshaft 15.

In accordance with the method of the invention, after separate die casting of the inner and outer fan members 31 and 33, the fan members are then assembled in interfitting relation to provide the desired alignment and to provide for rotatably driving one of the fan members from the other fan member. Thereafter, the nut 99 is assembled to the crankshaft 15 to prevent disassembly of the fan members 31 and 33, one from another.

Means other than the nut 99 could be employed for retaining the fan members in assembled relation. For instance, a screw or other fastening member could be employed to fasten the hubs 61 of the outer fan member 33 to the hub 35 of the inner fan member 31.

Various of the features of the invention are set forth in the following claims.

We claim:

1. A method of manufacturing a fan assembly including a flange extending radially outwardly in relation to the intended rotational axis, and a plurality of angularly spaced vanes each extending from the flange in generally radially outwardly projecting relation to the intended rotational axis and having an outer part extending arcuately in a plane extending parallel to the intended rotational axis and perpendicularly to a plane extending radially from and containing the intended rotational axis, said method comprising the steps of die casting a first fan member with the flange and with a plurality of angularly spaced vane portions projecting from one surface of the flange, die casting a second fan member with a second plurality of vane portions corresponding in number and angular spacing to the vane portions of the first fan member, each of the second member vane portions including the vane outer parts, aligning the first and second fan members to locate the vane portions in alignment, and assembling the first and second fan members with the vane portions in alignment and so as thereafter to maintain the vane portions in alignment.

2. A method in accordance with claim 1 wherein the outer parts of the vanes of the fan assembly have an axially outer margin and wherein said step of die casting said first fan member utilizes a parting line extending along said one surface of said flange and wherein said step of die casting said second fan member utilizes a parting line extending along the axially outer margin of said vane outer parts.

3. A method of manufacturing a fan assembly including spaced walls defining a radially open circumferentially extending air outlet and an axially open air inlet, and a plurality of angularly spaced vanes each extending between the walls, said method comprising the steps of die casting a first fan member with a flange extending in radially outward relation to the intended rotational axis, and with a plurality of angularly spaced vane portions projecting from the flange in radially outwardly extending relation from the intended rotational axis and having outer parts, die casting a second fan member with a cylindrical portion defining, at one end thereof, the axially open air inlet, and with a second plurality of vane portions extending radially inwardly from the cylindrical portion and corresponding in number and angular spacing to the vane portions of the first fan member, and with a flange extending radially outwardly from the other end of the cylindrical portion, aligning the first and second fan members to locate the vane portions in alignment, and assembling the first and second fan members with the vane portions in alignment and with the second member flange extending in adjacent relation to the radially outer parts of the vane portions of the first member so as to define with the first member flange the circumferentially extending air outlet and so as, thereafter, to maintain the vane portions in alignment.

4. A method in accordance with claim 3 wherein the vanes of the fan assembly each have an inlet section extending arcuately in a plane extending parallel to the intended rotational axis and perpendicularly to a plane extending radially from and containing the intended rotational axis and wherein the step of die casting the second fan member includes die casting the vane portions of the second member with the vane inlet sections.

5. A method in accordance with claim 3 wherein the step of die casting a first fan member includes casting thereof with a hub extending from the flange and from the radially inner ends of the vane portions and wherein the step of die casting a second fan member includes casting thereof with a hub extending from the radially inner ends of the vane portions of the second fan member, and wherein the step of assembling the first and second fan members includes assembling thereof with the hubs of the first and second fan members in alignment. 

1. A METHOD OF MANUFACTURING A FAN ASSEMBLY INCLUDING A FLANGE EXTENDING RADIALLY OUTWARDLY IN RELATION TO THE INTENDED ROTATIONAL AXIS AND A PLURALITY OF ANGULARLY SPACED VANES EACH EXTENDING FROM THE FLANGE IN GENERALLY RADIALLY OUTWARDLY PROJECTION RELATION TO THE INTENDED ROTATIONAL AXIS AND HAVING AN OUTER PART EXTENDING ERCUATELY IN A PLANE EXTENDING PARALLEL TO THE INTENDED ROTATIONAL AXIS AND PERPENDICULARLY TO A PLANE EXTENDING RADIALLY FROM THE CONTAINING THE INTENDED ROTATIONAL AXIS SAID METHOD COMPRISING THE STEPS OF DIE CASTING A FIRST FAN MEMBER WITH THE FLANGE AND WITH A PLURALITY OF ANGULARLY SPACED VANE PORTIONS PROJECTING FROM ONE SURFACE OF THE FLANGE DIE CASTING A SECOND FAN MEMBER WITH A SECOND PLURALITY OF VANE PORTIONS CORRESPONDING IN NUMBER AND ANGULAR SPACING TO THE VANE PORTIONS OF THE FIRST FAN MEMBER EACH OF THE SECOND MEMBER VANE PORTIONS INCLUDING THE VANE OUTER PARTS ALIGNING THE FIRST AND SECOND FAN MEMBERS TO LOCATE THE VANE PORTIONS IN ALIGMENT AND ASSEMBLING THE FIRST AND SECOND FAN MEMBERS WITH THE VANE PORTIONS IN ALIGNMENT AND SO AS THEREAFTER TO MAINTAIN THE VANE PORTIONS IN ALIGNMENT.
 2. A method in accordance with claim 1 wherein the outer parts of the vanes of the fan assembly have an axially outer margin and wherein said step of die casting said first fan member utilizes a parting line extending along said one surface of said flange and wherein said step of die casting said second fan member utilizes a parting line extending along the axially outer margin of said vane outer parts.
 3. A method of manufacturing a fan assembly including spaced walls defining a radially open circumferentially extending air outlet and an axially open air inlet, and a plurality of angularly spaced vanes each extending between the walls, said method comprising the steps of die casting a first fan member with a flange extending in radially outward relation to the intended rotational axis, and with A plurality of angularly spaced vane portions projecting from the flange in radially outwardly extending relation from the intended rotational axis and having outer parts, die casting a second fan member with a cylindrical portion defining, at one end thereof, the axially open air inlet, and with a second plurality of vane portions extending radially inwardly from the cylindrical portion and corresponding in number and angular spacing to the vane portions of the first fan member, and with a flange extending radially outwardly from the other end of the cylindrical portion, aligning the first and second fan members to locate the vane portions in alignment, and assembling the first and second fan members with the vane portions in alignment and with the second member flange extending in adjacent relation to the radially outer parts of the vane portions of the first member so as to define with the first member flange the circumferentially extending air outlet and so as, thereafter, to maintain the vane portions in alignment.
 4. A method in accordance with claim 3 wherein the vanes of the fan assembly each have an inlet section extending arcuately in a plane extending parallel to the intended rotational axis and perpendicularly to a plane extending radially from and containing the intended rotational axis and wherein the step of die casting the second fan member includes die casting the vane portions of the second member with the vane inlet sections.
 5. A method in accordance with claim 3 wherein the step of die casting a first fan member includes casting thereof with a hub extending from the flange and from the radially inner ends of the vane portions and wherein the step of die casting a second fan member includes casting thereof with a hub extending from the radially inner ends of the vane portions of the second fan member, and wherein the step of assembling the first and second fan members includes assembling thereof with the hubs of the first and second fan members in alignment. 